The present invention relates to real-time-MRI-guided radiofrequency (RF) cardiac tissue ablation.
Real-time-MRI-guided radiofrequency (RF) cardiac tissue ablation can be used for treatment of conditions such as cardiac arrhythmias including atrial fibrillation (AF). RF ablation is a minimally-invasive catheter-based procedure in which RF energy is used to create lesions in the atrial wall in a prescribed manner to isolate ectopic electrical activity.
During RF ablation procedures, accurate knowledge of contact made between catheter tip and the structure to be treated, for example the left atrial (LA) wall, is crucial for success of creating the lesion, for accurate electrocardiogram measurement, and for ensuring patient safety.
However, the monitoring of tip-tissue contact, which is currently being performed using X-ray or ultrasound technologies, is a known shortcoming of current real-time MRI technology. During RF ablation, commonly used to treat cardiac arrhythmias such as atrial fibrillation, scars are intentionally created in the atrial wall to isolate the sources/triggers of abnormal electrical activity. The success rate of RF ablation is limited by the poor imaging that is currently clinically available, generally using X-ray projection imaging and intracardiac echo (ICE). X-ray imaging has poor soft-tissue contrast and only provides projection views. Ultrasound/ICE catheter positioning is cumbersome and provides only limited wall visualization. Visualization of the catheter tip visualization over a static atrial shell does not provide real-time relative positioning of the catheter tip and the wall.
Poor imaging guidance results in the inaccurate deposition of RF energy and, consequently, can lead to errors in the intended locations of the scars. This may result in the incomplete electrical isolation of the arrhythmia triggers and, in turn, the recurrence of symptoms.